The video strings together a series of clips of Gomez touting his work in the private sector, "actually helping companies grow and be successful," he says during one GOP primary debate.
It goes on to include clips of him being asked about his client list over multiple consecutive appearances on a local news show, during which he eventually says that it's the firm's decision whether or not they want to release his client list.
The Massachusetts Democratic Party is also holding a press conference to highlight the issue on Friday, at which Chairman John Walsh will castigate Gomez for attempting to "hide" his clients from the public, according to prepared remarks provided to The Hill.
"Gabriel Gomez's refusal to disclose the names of his clients is more than just a potential ethics violation – it suggests that he has something to hide, and it's time for Gomez to finally come clean with the people of Massachusetts by disclosing the names of his clients," Walsh will say.
Gomez's client list became an issue for the Republican earlier this week when a progressive-leaning government watchdog group, Citizens for Responsibility and Ethics in Washington, filed an ethics complaint against Gomez for failing to release those details.
His campaign has said the candidate was not required to disclose additional information as he provided consulting services to Advent International, not specific clients of Advent.
“This is a merit-less, partisan attack from a liberal-advocacy group," said Gomez spokesman Will Ritter following the initial ethics complaint.
And Gomez adviser Lenny Alcivar charged Markey with "hypocrisy," noting that his campaign redacted his address when it released his tax returns.
"Ed Markey won't even tell us which address he puts on his tax returns. He refused for 37 years to even release his tax returns. He bounced checks at the House bank. We're not listening to lectures from Congressman Markey on disclosure. This kind of hypocrisy is one more reason we need to get rid of arrogant career politicians in Washington," he said.
But Democrats are banking on the attack as a way to potentially neutralize one of Gomez's biggest strengths in the race: his business background.
Gomez has argued that his business and military background make him better-suited for the Senate than Markey, who has served nearly four decades in the House.
Massachusetts Republicans are betting that dissatisfaction with Washington is strong enough that Gomez's outsider status and his private sector experience will be enough to outweigh the heavy pull of the national GOP and President Obama's popularity in the state.
Attacking GOP presidential nominee Mitt Romney's business background saw some success in 2012, and Democratic attempts to characterize his work in private equity as shadowy at best helped take the issue out of the successful businessman's arsenal.
Though Markey leads Gomez in every poll of the race, the Republican has managed to keep his lead largely down to single digits, and multiple nonpartisan race rating publications have shifted the race to be slightly more favorable to the Republican in recent weeks, though Markey still remains the frontrunner.